


The Titan Instruments

by Currently_Obsessed



Category: Shingeki no Kyojin | Attack on Titan, The Mortal Instruments Series - Cassandra Clare
Genre: Crossover, Kenny Ackerman is a Dick, M/M, Monsters, Not Strictly based on either stories, Yeager spelt Jeager
Language: English
Status: In-Progress
Published: 2018-02-10
Updated: 2018-02-10
Packaged: 2019-03-15 14:42:09
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 3,588
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13615527
Author URL: https://archiveofourown.org/users/Currently_Obsessed/pseuds/Currently_Obsessed
Summary: Little did Eren Jeager know how meeting a mysteriously hot (if rather rude) guy at Pandemonium - a club he was meant to play at with his best friend Armin Arlert- would change his life.But when he returns home after seeing said guykill someone, he finds his dear mother missing, and Mikasa, Carla Jeager's "witch" friend, sends him away while they're attacked by other weird guys with shiny swords, and Mr. Rude appears as some sort of Knight in Shining Armor, Eren resigns himself to have his whole life turned on its head.Because apparently Mikasa and his mother hid many secrets. Secrets related to his missing memories, his father's death, and his mother's supposedly dead ex, Kenny Ackerman...





	The Titan Instruments

**Author's Note:**

  * For [BrytteMystere](https://archiveofourown.org/users/BrytteMystere/gifts).
  * In response to a prompt by [BrytteMystere](https://archiveofourown.org/users/BrytteMystere/pseuds/BrytteMystere) in the [FYEF_2018](https://archiveofourown.org/collections/FYEF_2018) collection. 



> **Prompt:**
> 
> (Original spelling from their prompt)  
>  
> 
> Little did Eren Jäger know how meeting a mysteriously hot (if rather rude) guy at Pandemonium -a club he was meant to play at with his best friend Armin Arlert- would change his life.
> 
> But when he returns home after seeing said guy _kill someone_ , he finds his dear mother missing, and Mikasa, Carla Jäger's "witch" friend, sends him away while they're attacked by other weird guys with shiny swords, and Mr. Rude appears as some sort of Knight in Shining Armor, Eren resigns himself to have his whole life turned on its head.
> 
> Because apparently Mikasa and his mother hid many secrets. Secrets related to his missing memories, his father's death, and his mother's supposedly dead ex, Kenny Ackerman...

**Notes for the Chapter:**

> I'm writing this before it's done. I want to see how long I can make it. I want it to be very long. Let's see if I can too it! I'll add a note at the end if I succeed.╭(╯^╰)╮

I sighed as I sketched the same symbol into my notebook over and over again. It looked like a pair of wings that crossed over each other. One simply white while the other is shaded in. It had been stuck in my head since last week from this stupid dream that kept coming back no matter how hard I tried to rid myself of it.

I had only shown my best friend Armin since I knew that he wouldn't judge me for something that weird.

If I had shown my mother, she might have freaked out over it just like everything else that happens.

She always seems a bit paranoid about something. And because of that, she has a strict set of rules for me. No staying out late. Always have my phone on me. Never talk to strangers. No friends over at my place. Not even Armin is aloud over.

It sucks. 

She acts like someone is out to get us or whatever.

I sigh again as Armin's familiar blond hair comes into view. We planned to meet up for my birthday since I wasn't able to have a party. Instead, we chose to meet at a local coffee shop, The Titan Café, and spend time together. 

"Hi, Eren!" He nearly chirps. I smile at him as I sip my tea. I always liked it better than coffee. Especially with a hint of honey instead of sugar. 

"Hi," I reply. "Did your grandpa finally help you get that new book you wanted?"

He nodded with enthusiasm. His blue eyes lit up like a Christmas tree when he started going on and on about how good it was. I couldn't help but laugh at his antics. He was a huge book nerd, but we have been best friends since kindergarten so I was used to him getting excited about worlds that only existed on paper.

This latest one was the first book of a new series he wanted to read. It was about a world that only existed behind a wall with man-eating giants laid beyond and humanity struggled to rid the world of them. And one of the main characters turns out to be able to turn into one of those monstrous creatures. 

"That sounds like a good read. I'll have to borrow it when you're done," I teased, knowing how he is with his books. He looked offended that I even thought about borrowing one of his treasured items. If there was one thing that he knew about me more than anything was that I am a total slob when it comes to stuff like books. I always dog-eared pages and left them open.

Or I would use whatever was closest to me for a bookmark. One time, I laid an open book face down and almost ruined the spine, and Armin didn't speak to me for a week!

"I'm kidding, Ar, geez. You need to relax," I said, nudging his shoulder. He eyed me suspiciously. 

"Mhmm," he said into his cup. After that, we had an easy conversation. We spoke a bit about a few upcoming assignments for school. I also told him that I needed to be home early today for some reason that my mom wouldn't even give me other than 'because I said so.'

What a bore.

"Hey, I heard that they are opening up this new club close to here. It's supposed to be more 'teen-friendly,'" I said, using air quotes. "I was thinking about you and me going there for a small gig if mom allowed me too. I could get Ymir to play drums again and maybe Historia to do some back up singing. She does have a pretty voice. And you know that she's always a crowd pleaser." He nodded.

"That she is. Too bad she can't meet new people because of Ymir," Armin added.

I laughed. "Right, like Historia has any intention of dating anyone other than that freckled bitch," I said ever so lovingly.

Ymir may have been rude, but she and I had a mutual understanding of one another. It was like we were cut from the same cloth. She spoke her mind and didn't take anyone's shit, kinda like me. But unlike me, she knew how to pick her battles. She would back down if she knew that there was no way that she could win a fight.

Unless there was something that was threatening Historia. That's the only time that she would lose her shit and completely obliterate the threat.

"True. Hmm. I'll see if I can ask my grandpa if I can come. I know that you need me to keep you in line after all. I'm like 99% of your impulse control." He laughed that teasing, cheerful laugh of his. Don't let that sweet face of his fool you. He is a diabolical little shit when he wanted to be. My neighbor and class rival, Jean, won't even look him in the eye anymore because he thinks that Armin is a wolf in sheep's clothing.

"So, I'll try to convince mom and you call Connie and Ymir?" I asked. He chuckled.

"Yeah, good luck. OH! I nearly forgot." He reached down and pulled up a small gift bag. "Here you go!" I smiled and took the gift bag. 

"Thank you, Ar, but is it okay if I open it at home? I didn't realize how late it is," I said as my phone dinged.

We said our goodbyes and i rushed out of the café.

But on my way out, I nearly ran into a man a few years older than me who had raven hair styled in an undercut. He was maybe 19, at most. His gunmetal gray eyes bore into mine like I was just dirt on his boots. But his eyes widened a bit in surprise as I addressed him.

"Sorry, I was in a hurry and wasn't paying attention," I walked around him and saw on his arm, a tattoo that symbol of the two wings peaking just below the rolled up sleeve of his white dress shirt. I edged around him and saw a glimpse of his group he was with.

A small strawberry blond, a taller teen with a blond curly undercut, a blond with a man bun and a guy whose black hair I can only picture as an onion. It would have been funny if I wasn't in such a rush to get home. I didn't need to be late again. 

I caught each of their eyes for a split second before I ran down the sidewalk towards my house. I could have sworn that one of them say something along the lines of 'shitty brat' as I continued on my way.

* * *

My house wasn't too far from the café. On East Shinganshina Street. It was a small one story with a finished basement that was my father's home office.

"Mom, I'm home!" I called out as soon as I opened the door. I locked it behind me and went into the kitchen. Mom was cooking dinner with her hair loosely tied off to the side so it didn't get in her face as she cooked.

"Hi, honey. What did Armin get you for your birthday?" She asked. I held up the bag.

"Hadn't looked yet," I admitted.

I set the bag on the counter and pulled out a card as well as a neatly wrapped box of some kind. I tore open thr wrapping paper and opened the little box. Inside was a small pocket knife that I had been eyeing for a while. 

"Ah, nice!" I cheered. Mom giggled. 

"Armin really knows you really well. Take that with you everywhere, but not to school!" She said. I rolled my eyes. I knew that already. Nobody was allowed pocket knives at school. What did she think I'm dumb or something?

"Oh that reminds me, I wanted to see if I could catch a big at the new club, Pademonium, with my band," I said. Her expression changed in an instant. It went from light and breezy to shocked and stern.

"Absolutely not! I'm sorry Eren, but no. I can't lose you if something happened while you were there," she said. I slumped. I knew it.

"Yeah, okay. I'm sorry. Any way. I have home work to do," I said with a smile. She pet my hair and went back to cooking. 

I left and headed to my room. I pulled out my phone and texted Armin that mom said I could, but he instantly called me on my bullshit.

Armin:  _Just sneak out, I know you're planning on it anyway._

Eren: _I am n-...._

Eren:  _I'll see you at 10._

* * *

I had my guitar already hidden in the bush by my bedroom away before dinner, so I didn't have to sneak it out of my window with the big guitar and amp on my body. I'd so get caught if I tried that.

I landed with a soft oof, and quickly grabbed my stuff. I spotted Ymir's Slam Van a few houses from mine and booked it towards the Hippie Mobile, as I so lovingly call it. I nod my silent greeting to everyone inside and put my stuff next to Ymir's drum set. 

"I can't fucking believe you managed to sneak out with your overbearing mom," Ymir teased as I closed the door behind me.

"Oh hardy har har." I rolled my eyes as I said this.

Armin sighed as I sat between him and Connie. "Hey man, glad you could make it! Ymir called ahead and actually managed to book us a spot!" Connie cheered. I smiled.

"Sweet! I figured if anyone could, it would be her. Well, her or Historia," I said with a playful push to the blond in the passenger seat. 

"Why's that?" She said, sweetly.

We all gave her a knowing look; even Ymir, who tried to focus on driving. She blushed and averted her eyes. I rubbed her shoulder in what I hope was seen as comfort. 

After that, we drove in silence. We made it to the new club within 20 minutes and all piled out. Ymir checked us in with the bouncer as we gathered out stuff. We were lead back behind the stage to set up everything. Historia hummed in different notes to get her voice ready for what might be a long night.

I sat off to the side and made sure my guitar was tuned properly, tweaking it if needed.

Ymir and Connie put her drums together. Armin made himself useful by making sure the microphones were all set up and that Connie's bass was all set up and ready for him. I heard the dj playing some of No Names songs and heard the rhythm of people moving to the beat of the heavy metal song. 

Which was weird to hear from a club. But, hey, if they were having fun, who am I to judge?

I actually really liked No Name.

"You guys ready?" I asked. "After this song, we should be able to start." Everyone nodded and smiled, the underlying excitement of tonight was getting to us. 

"Alright. I'm going to go get a drink real fast, since this song isn't even half way over yet," I said as I clapped Armin on the shoulder. I made my way past him to the small non-alchoholic bar and ordered a water bottle. I drank while looking over the crowd. 

Thats when I saw a familiar face. The guy I nearly ran into earlier today at the café. His bored, gray eyes searching through the crowd. I noticed that he was alone now. And that, while he was in the middle of the crowd, he was not dancing, and everyone seemed to ignore him entirely. 

He made his way to the bar and sat down, not saying anything to the bartender. From this close up, I saw how short he was. Maybe 5'3? His feet didn't even reach the floor when he sat on the stool, unlike mine where the toes of my shoes scraped along it.

I couldn't help but watch him with interest. I had never seen him at my school, or anywhere in the neighborhood before. He must have felt me watching him, because his eyes cut over to mine. Again he seemed surprised. Though we were several seats away from each other, I could see the confusion and anger in his dark eyes.

He got up and left after that.

I shrugged and went back to my friends. That guy is just plain weird.

I headed backstage and on my way back I spotted one of the people that that guy was with. It was the girl. Curiosity got the better of me and I followed her. She met up with the curly blond guy and they headed further back than my band was allowed. 

My heart pounded in my chest as I did. Clearly they were doing something they weren't supposed to. They met up with the guy who just left the bar and I got as close as I could to listen to what they were talking about,

"That brat saw me. Even with the glamour on. This is going to hell quickly. If Erwin knew that someone could see us, then he'd probably want them. The covenant can onky be spotted by other Shadowhunters. Meaning that that brat is one of us," he said.

He was clearly irritated.

The girl spoke up next. "Are you sure you even activated the rune, Levi? I mean Olou has done it before," she said, cutting a look to the blond next to her.

"Hey, at least I didn't piss myself on my first mission, Pet-" He bit his tongue which immediately started bleeding. 

"That's what you get for flapping your jaw, Olou," she teased with a flirtatious push. Olou blushed slightly and turned back to the other guy, Levi.

"Let's just find this demon before anyone else gets hurt, or worse," Olou said. "Is Gunther and Eld in place?"

"They better fucking be or else I'll have their fucking heads," Levi said, pulling out a dagger of some kind from his jacket. I widened my eyes at the sight of the glinting silver. They continued on and went through another set of doors.

I quickly and quietly followed them, not caring that my band was probably waiting for me at this point. I went through the double doors and saw that this was a storage area of some kind. I heard more talking. I rounded a shelf and saw four of them all surrounding a frantic looking man. He had brown hair and was rather plain looking. 

They each had daggers like levi had, but he is nowhere to be seen. 

"I know what you are, demon! You're not leaving here alive!" Olou said, almost like he was mimicking Levi. The frantic man finally stopped shivering in fear. Instead he started laughing. 

"Oh, how cute. You think that it will all stop once you kill me, huh. You'll go back to your boss like nothing mattered and that this was a job well done. You can tell that fucker that his uncle says hello-" A dagger went through the back of his neck and stuck out to the front, just under his Adam's apple. 

I couldn't stop the scream as it forced it's way out of my mouth. Black blood spilt from the man and he fell to the ground, steaming inhumanly.

All eyes were in me.

"SHIT!" The guy with the man bun yelled. They all ran towards me after putting away their weapons but I ran. I didn't know where, but I just ran. 

I knocked over boxes and rounded shelves in order to get away from them. 

I didn't make it far as someone landed on top of me. "Oi, brat! It's fine, that thing wasn't human. It onky took human form!" Levi's voice gritted out into my ear lowly.

I whimpered from my place in the floor. I don't even know where he came from.

"Let me explain. But first, you need to go home. I'll follow you," he said, not even giving me a choice. That bastard.

"Why the hell should I?" I demanded underneath Mr. Rude. He snarled into my ear, gripping my hair, pulling harshly.

"Because I need to warn my boss about you, dipshit!" He ground out.

"Um, Levi?" The girl started. Levi sighed and dropped my hair. My head fell and hit the concrete floor. I groaned in pain. 

"What, Petra?" He demanded. 

"Erwin is on the phone. It's for you," she said, holding out an iPhone toward him. He rolled his eyes took it. He turned sharply towards the man bun guy.

"Make sure the brat gets home safely, Eld." Eld nodded. So if man bun was Eld, that makes onion head Gunther. 

Eld helped me stand and led me out of the club. I sent a quick text to Armin and told him that my mom found out that I snuck out and that I needed to be home.

He believed me and just said he'd drop off my stuff after they were done. And that the others were doing fairly well despite me not being there as lead singer and guitarist.

Eld took me to a nice town car and drone me to my house. I had to give him my address or else I wasn't allowed to leave at all. I sighed as I stepped out and followed him up to my bedroom window. I snuck back in, Eld following me.

"I wish Mike was here," he whispered. "I don't like not know what could be here." He said, hand in his jacket, most likely on his dagger.

"Whoa, buddy, I doubt that there's anything in here other than my sleeping mother," I said as I stepped out of my room. The house was dark, but rightly so. It was just after 1 am. Adrenaline filling my body, keeping the sleep out of my system for now. 

Eld was eerily quiet as he stepped in front of me. He had the look of a hunter. A predator looking for it's next meal.

"Stay here," he said, causing the hairs on my arms to stand on end. He was clearly sensing something that I wasn't. 

I felt my heart jump into my throat and I held my breath as Eld pulled his dagger out with one hand and a phone in his other. He sent out a message to his friends presumably and went back to hunting.

 "Which room is your mother's?" He asked. I pointed out here and we headed down the hall towards it. Something was wrong. The house now felt too cold. Too empty. Too quiet.

My eyes flicked towards every dark shadow cast as if something was going to jump out at any moment.

I looked at Eld's tense back as he pushed my mother slightly ajar door open further. I gasped slightly.

"She would never sleep with her door open," I whispered. My pulse quickened further as we stepped into her room. "Oh dear god."

Her room was _trashed_.

Her lamp shattered, on the other side of the room; her bed turned on its side, blankets and pillows strewn about; drawers pulled out of the dresser, and her clothes everywhere; pictures of her and my late father smashed or torn to shreds. 

I nearly blanched at the sight of it all. But most disturbing parts were that she was missing and I now felt something watching us.

Eld must had felt it too, because he spun around and thrust his dagger at a dark figure, but it was grabbed by a pale hand. 

"You idiot!" Levi's rude voice said into the dark. "Mike is here now, so we should know if this was done by a Downworlder, or demon," he said. 

Eld nodded. 

"What are you people?" I asked. But my question went ignored.

"Do you have a place to stay?" Levi asked. I couldn't stay at Armin's, if this happened while I was away, I couldn't put Armin in that same danger. I thought about a mutual friend on my mom's. A black haired girl my age with not much emotions shown on her face or in her dark eyes. I knew her almost as long as I knew Armin, since we were 9. 

She was going to get kidnapped by three men when I came with my mom and I stopped two of them. She stopped the third. 

I nodded and looked at Levi. He actually reminded me of her now that I think about it. But he is far ruder than she is.

"Her name is Mikasa," I said. "I could stay there." 

"Mikasa Ackerman?" Levi asked. I nodded. "Thank fuck, I trust her actually. I'll have Eld and Mike take you there when we're done here." 

"Can you at least tell me what's going on?" I asked. "Things are happening too quickly." I head my head as a headache came full force. I was forced to sit on the floor and put my head between my knees. Between seeing what I did at Pandemonium, getting hit in the head, and now this, I'm surprised that I haven't had a stress headache sooner. 

"Breath, Kid. I don't need you to pass out on me now," he said. "And long story short, your mother was kidnapped."


End file.
